This invention relates to position-sensing apparatus. It is known, e.g. in numerically controlled machine tools, to provide a spindle having an axis of rotation, a support structure supporting the spindle for rotation, a probe having a body secured to the spindle for rotation therewith about said axis, the probe further having means for sensing an object, means for generating a signal responsive to such sensing, and external transmission means for transmitting the signal from said body to a location provided on said support structure at a given angular position about said axis. Said angular position is so selected that the external transmission means does not foul other equipment present on the support structure. However, it is often desirable to rotate the probe by rotating the spindle, e.g. for the purpose of a particular measuring manouvre. In the past such rotation was not possible because of the selected angular position of said location.